Ball Lock Pin Redundant Spring Locking Against Unintentional Release
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Solution Overview
Problem
Conventional ball lock pins fail to meet European Aviation Safety Agency (EASA) certification specifications for helicopters, as they lack double locking mechanisms, leading to potential Foreign Object Damage (FOD) due to spring failure or breakage, which can result in unintentional unlocking.
Innovation Solution
A ball lock pin design incorporating a primary and redundant spring element with a blocking pin that moves between locking and releasing positions, ensuring the locking balls remain in place even if the primary spring fails, and featuring a dedicated unlocking tool to prevent unintentional actuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional ball lock pin with a single compression spring is used, then the device complexity is low, but the reliability is insufficient due to potential spring failure or lock pin breakage
Solution Approach 1:
The patent implements a redundant spring element that serves as a backup mechanism. If the primary compression spring fails or the blocking pin breaks, the redundant spring element maintains the blocking pin in the blocking position, ensuring the locking balls remain secured and preventing unintentional unlocking. This beforehand cushioning approach directly addresses the reliability issue by preparing a backup system in advance.
Solution Approach 2:
The patent changes the numerical parameter of the spring element quantity from one to two, creating a redundant system. This parameter change transforms the single-point-failure conventional design into a fail-safe configuration where the failure of one spring element does not compromise the overall locking function.
2Ease of operation
If the blocking pin is made accessible for actuation, then the ease of operation is improved, but the risk of unintentional actuation increases
Solution Approach 1:
The patent introduces a tool-operable feature as an intermediary between the user and the blocking pin actuation mechanism. This intermediary requires a specific tool to activate the blocking pin, maintaining ease of operation when needed while preventing unintentional actuation during normal handling or maintenance activities.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design provides a fail-safe double locking mechanism that complies with EASA certification specifications, ensuring the ball lock pin remains secured in the length direction and prevents unintentional unlocking, enhancing safety by maintaining the locking position even in case of primary spring failure.
Implementation Method 1
a spring element arranged in the inner accommodation and configured to bias the blocking pin into the blocking position
Data Source
AI summary
A ball lock pin comprising a pin body with an inner accommodation and at least one locking ball accommodation; a blocking pin at least partly arranged in the inner accommodation and movable between a blocking position and a releasing position; at least one locking ball movably arranged in the at least one locking ball accommodation and biased into a locking position by the blocking pin, if the blocking pin is in the blocking position, wherein the at least one locking ball is released for moving into an unlocking position if the blocking pin is in the releasing position; a primary spring element arranged in the inner accommodation and biasing the blocking pin into the blocking position; and a redundant spring element arranged in the inner accommodation and biasing the blocking pin into the blocking position.